1. Field of the Invention
This invention relates to electrodes used for making contact with the surface or skin of the body, for monitoring and/or picking up electric impulses generated by the various parts of the body.
The class of electrodes to which the present invention is related finds great utility in medicine, for example, for diagnostic purposes such as for monitoring and/or picking up electric impulses generated by brain activity, i.e. brain waves for the electroencephalogram (E.E.G.) or for picking up electric impulses generated by heart activity for the electrocardiogram (E.K.G.). More recently electrodes have been used to pick up electric impulses generated by body parts for monitoring a patient in intensive care hospital units. A more recent use of electrodes is for the purpose of picking up electric impulse generated by muscular activity during exercise and/or skill enhancement activities for monitoring muscular activity, one purpose being for tuning coordination of interacting muscular activity, for example.
2. Prior Art
The class of electrodes to which the present invention is related is normally used to pick up electric information, such as electric impulses generated by the body, which directly relate to some body activity. This information need be accurate as possible, especially when the information is used for medical diagnostic purposes. The electric impulses generated by the body are very small and the body itself is a poor conductor. In order to accurately detect the body electric impulses good electrical conductivity between the electrode and the skin is most desirable. In order to achieve good electrical conductivity between the skin of a person on whom the electrode is used and the electrode element, many electrodes use suction cups to draw the skin into tight, intimate contact with the electrode. This suction on the skin is uncomfortable, especially if the electrode/suction cup combination is used over an extended period of time. Another technique used to achieve better electric contact is the use of conductive fluids and/or ointments in conjunction with the electrode. This is messy and often not practical.
U.S. Pat. No. 4,391,279 to Stein is an example of the prior art which discloses an electrode made in suction cup form. Stein's structure calls for the use of a conductive silicone rubber for the suction cup. A metal electrode in rivet configuration passes through the center of the suction cup and terminates in the form of a stud of a snap on fastener. Stein also suggests that the skin of the patient on whom his electrode is used, be coated with conductive gel or water to enhance conductivity. An earlier prior art U.S. Pat. No. 2,895,479 issued to Lloyd discloses an electrode which uses a sintered or porous metal disc over which a reservoir for a fluid is positioned. The reservoir is filled with water soluble electrolytes to overcome resistance of the skin and improve contact between the skin and the electrode. The electrode disclosed by Corbett in U.S. Pat. No. 4,537,198 provides for a sponge element to be attached to the electrode and saturation of the sponge by use of a conductive fluid is called for to enhance conductivity.